Heat exchange apparatus



May 15, 1934. A. zlsKA HEAT EXCHANGE APPARATUS Filed Feb. 18, 1932 N SElil/7111 l INENTOR. ,5 l5 36 kAch-1m Zz'skq ATTORNEY.

Patented May 15, 1934 UNITED STATES HEAT EXCHANGE APPARATUS Adam Ziska,Wauwatosa, Wis., assignor to A. 0.

Smith Corporation, Milwaukee, Wis., a corporation of New YorkApplication February 18, 1932, Serial No. 593,709

7 Claims.

This invention relates to heat exchange apparatus and especially toimprovements in the construction of a rotary drum which serves as a heattransfer element in apparatus in which the drum is intended to besubmerged in a liquor which is to be heated or cooled. In an apparatusof this kind, the liquor which is to be heated or cooled is placed in acontainer (not shown), and hot or cold uid is circulated through therotatable l0 heat transfer element.

It is an object of the present invention to provide a rotatable heattransfer drum to the inner and outer surface of which unobstructedaccess may be had during rotation thereof. Another object is to providea cooling drum which oifers small resistance to the rotation thereof ina liquor. A further object is to provide a selfpumping, rotary drumwhich may be provided with a baffle and/or a scraper adjacent the innerand the outer surfaces of the drum while the drum is being rotated. Afurther object is to provide a simplified mounting which consists of asmall number of parts and a minimum of joints through which leakage mayoccur. Other objects of the invention will be apparent from thefollowing description and the accompanying drawing.

According to the invention, a heat transfer element is constructed whichis capable of having its temperature changed at will while it isimmersed in a liquor for the purpose of controlling the temperature ofthe latter. The element is capable of conducting heat energy through itswalls and of being rapidly rotated to provide for a high rate of heattransfer through these walls. The construction of the element is suchthat its external conducting surfaces are readily accessible duringrotation of the element so that foreign material may be removedtherefrom and so that stationary means may be positioned adjacent tothese surfaces to prevent or reduce the tendency of the liquor in whichthe element is immersed from rotating with the element.

The following specic embodiment is an illustration of one mode ofcarrying out the invention but it is to be understood that the inventionis not limited thereto and that modifications may be made withoutdeparting from the invention.

In the drawing:

Figure 1 is a vertical cross-sectional View of the drum taken along line1 1 of Fig. 2;

Fig. 2 is a cross-sectional view of the drum taken along line 2-2 ofFigure 1 with part of the structure broken away to show the spiderstructure in greater detail; and

ing. yThe innermost and outermost walls 24 and mounted on a hollowspider 2 which spider is 60 secured to and rotated by a hollow shaft 3.The lower end of the shaft 3 is provided with a flange 4 integraltherewith. The flange is provided with holes 5 through which screws 6pass and extend into tapped holes 7 in a boss 8 which is an in- 65tegral part of the spider 2. The flange 4 is seated in a machined recess9 in the top of boss 8. The hollow shaft is divided interiorly into twolongitudinal passages 10 and 11 by a mid-web or partition 12 whichextends diametrically across the 70 enclosure and longitudinally of theshaft.

The spider 2 comprises a plurality of radiating arms or `members 13arranged substantially at equal distances apart. The arms are hollow andeach one is divided interiorly by a web or partition 16 which extendsdiametrically and horizontally across and along the interior of the arms13 to provide two passages 14 and 15. The passages 14 communicate at thecenter with the passage 10 in the shaft 3 through an opening 17 80 inthe boss 8. The passages 15 in `the lower part of the arms 13 are unitedcentrally of the spider to inclose the channel 18 which communicateswith the passage 11 in shaft 3 through an opening 19 in partition 16 andopening 20 in boss 8. Intercommunication between passages 14 and 15 andbetween passages 17 and 20 in the `boss 8 is prevented by an upstandingD-shaped flange 21 surrounding opening 19 and extending upwardly fromthe partition 16 to the boss 8 and to the partition 12. The lower end 22of partition 12 and the upper end 23 of flange 21 may be enlarged toprovide suicient bearing area so that an apertured gasket may besuitably positioned and properly supported to prevent leakage betweenthe flanged 'shaft 3 and the spider2.

Secured to and depending from the spider 2 is the hollow shell 1. Thisshell has a frusto-conical shape and has its larger diameter at itslower end. The walls of the shell comprise three spaced walls 24, 25 and26, each having a frusto-conical shape. The walls are relatively fixedby means of spacing blocks 27 which are positioned between the wallsand'secured thereto by welding or rivet- 26 extend downwardly beyond thelower end of the intermediate wall 25 and are secured together by anannular anged ring 28 welded or brazed thereto. A flange 29 on the ringextends into the space between the walls 24 and 26 and ts close- 110 lytherein. The welded union effects a uidtight seal at the lower end ofthe shell.

The upper ends of the walls 24, and 26 are staggered, the innermost wall24 extending upwardly the least distance and the outermostl wall 26extending upwardly the greatest distance. The upper end of the shell 1is sealed by an annular stepped. ring or band 30, asshown in Fig. 3. Theouter face of the band is cut away to provide the steps 31 and 32 whichprovide spacing means for the walls 24, 25 and 26, and annular seats ornotches 33 are cut in the steps to provide seats for receiving the endsof the walls 24, 25 and 26, where they are welded or brazed to the band30. Y

The band is secured to the outer ends of the arms 13 by welding, brazingor, preferably, by being integrally cast therewith. As shown in Figures1 and 2, openings 34 and 35 through the band 30 are made to align withpassages 14 and 15 respectively in each of the arms 13 of the spider 2.

The shell 1, spider 2 and shaft 3 are arranged about a common axis sothat the shaft and drum may be rapidly rotated. The spaced walls 24, 25and 26 form chambers 36 and 37 therebetween which communicate with eachother at the lower end of the shell 1 below the end of the interumediate wall 25. The upper end of chamber 36 vin the shell 1 and thencedownwardly through the chamber 37 to the bottom of the shell, around ythe lower end of Wall 25 into chamber 36, thence upwardly therethroughto the top of the shell, through opening 35 in band 30, passage 15 inspider 2, opening 19in partition 16, 0pening2 in boss 8 into passage 11in shaft 3. The circulated fluid should be so directed as to effectcontact with substantial and distributed portions of the walls of thedrum.

Positioned in contact with the outer surfaces of walls 24 and 26 areScrapers 38 and 39 which extend substantially the length of the cylinder1 and serve to keep the cooling surfaces of the drum clean. The Scrapersare held in position by brackets or supports 40 and 41 which may besecured to the wall and/or bottom of the container for the liquor. Theblades of the Scrapers may be positioned substantially normal to thesurfaces of the drum or they may be positioned at an angle thereto so asto either scrape or drag the surface of the drum.

The above described structure constitutes a heat transfer element whichmay be submerged in a fluid and rapidly rotated. The rapid rotation ofthe structure in the liquor will erode and tendtodestroy the normallystagnant :film of fluid which adheres to the surfaces of the structureand, hence, will enhance the rate of transfer of heat between thestructure and the liquor. In addition, the centrifugal forces whichresult from rotation of the frustoconical drum will cause the liquor tocirculate axially through the rotating drum. On account'of the angularrelationship between the surfaceV of the drum and its axis of rotation,the resultant components of ing movement brings fresh liquor in contactwith the heat conducting surfaces of the drum and hence increases therate of heat transfer.

In effecting a transfer of heat between the drum and a liquor, solidsand gases if present in the liquor tend to adhere so tenaciously to theheat transfer surfaces of the drum that they will not be removed by theerosive action of the liquor. When this occurs, the rate of heattransfer is materially reduced. The deposits are removed or reduced andthe efficiency of heat transfer is improved by contact members orScrapers which are arranged to bear on the heat conducting surfaces ofthe drum. By providing a support in the form' of a spider which isattached at one end or intermediate the ends of the drum so as to occupyonly a relatively small area of the surface of rotation which areaextends over a comparatively short axial distance of the drum, anopening'or openings are provided so that scraping arms can be disposedon the inside as well as on the outside surfaces of the drum and theheat transfer coefficient of the unit can be correspondingly increased.It has been found that a unitary perforate support which is afforded bya spider having radiating arms which are attached in the describedmanner is a sufficient support for the drum, that itprovides a structurewhich avoids interference with Scrapers forthe inside and the outsidesurfaces of the drum and permits circulation of the liquor through thedrum.

The invention is not limited to the particular arrangement of thestructural details described and illustrated in the specific embodiment.For example, the interwall structure of the shell may be variouslypartitioned to provide other paths for the course of the fluid.lElectrical resistance elements maybe distributed within the shell withleads therefrom extending into the shaft for the purpose of heating theshell. The shell may be perfectly cylindrical and other means may beprovided for circulating the liquor in which the drum is immersed, andvarious other modifications in the structure may be made withoutdeparting from the invention.

l.' claim:

1. A heat exchange apparatus which comprises a drum having spaced wallmembers and a partition therebetween which forms supply andreturnpassages through the wall for circulating liquids, a support having armsattached to thek drum within a relatively small area of the surface ofrevolution of the drum, said arms having longitudinal supply and returnpassages which are arranged to communicate with the supply and returnpassages of the drum respectively; a seal on the edges of the outsidewalls, said seal being spaced from said partition to providecommunication between the supply and return passages, a rotatable shafthaving longitudinal passes therein, and apertured means for mounting thesupport on the shaft with the passages in the shaft separatelycommunicating with the supply and return passages in the arms of thesupport.

2. A heat exchange apparatus which comprises a heat-conductive,frusto-conical drum which has spaced walls, a liquid-tight seal at oneend of the drum whichcloses the space between the edges of the walls,and a partition positioned intermediate and in a spaced relationship tothe walls, said partition terminating short of the sealedend of the drumthereby forming a supply and return passageway within the drum, meansextending across the edges of the spaced walls andthe partition forattaching the other ends of the wallsl and partigr.

tion, said means having supply and return apertures that are arranged tocommunicate with said supply and return passageways, and a supporthaving arms which are secured to said means, said arms having supply andreturn passages which are arranged to communicate with said supply andreturn apertures. p

3. A heat exchange apparatus which comprises a heat-conducting drumhaving a passageway within the wall of the drum for distributing meansto control the temperature of the drum, said drum being open at its endsand having a circular crosssection at right angle to the axis of thedrum, and means for rotatably supporting the drum having passages forfeeding and discharging said heat control means at one end of the drum,said supporting means being secured to said drum in an area having acomparatively short dimension as measured along the axis of the drum.

4. A heat exchange apparatus which comprises a heat-conducting drumwhich is open at its ends and has fluid-conducting passages in itswalls, and perforate means positioned at one end of the drum forsupporting and rotating the drum about its axis, said means havingpassages which communicate with the opposite ends of saidfluidconducting passages.

5. A heating device which comprises a drum which is open at the ends andis capable of being submerged in a liquor and of being rotated about itsaxis, spaced wall members in the drum having supply and return passagestherebetween for distributing heating means therein, a support for thedrum having transverse and longitudinal channels, said longitudinalchannels at one end of the drum communicating with the ends of saidsupply and return passages in the wall, a rotatable hollow shaft axiallydisposed to the drum, and means for mounting the shaft centrally on saidsupport, said support having ports which form communication between thehollow shaft and said channels.

6. A heat exchange apparatus which comprises a heat-conducting drumwhich has a circular cross-section normal to its axis, said drumoomprising spaced walls, a seal at one end of the drum which closes thespace between the edges of the walls, and a partition positionedintermediate and in a spaced relationship to each of the Walls, saidpartition terminating short of the sealed end of the drum and extendingto the other end of the drum thereby forming a supply and returnpassageway within the drum, an annular member or ring secured to saidother end of the drum and extending across the edges of the spaced Wallsand the partition, said member or ring having annular grooves on theouter face thereof which grooves form steps to which the edges of thewalls and partition are fastened and said member or ring also havingapertures therethrough which communicate individually with the supplyand return passageways in the drum, and a spider which has hollow armsradiating to and secured to said stepped rings at the apertures therein,said hollow arms forming supply and return passages which communicateindividually with the apertures in the stepped ring.

7. A heat exchange apparatus which comprises a heat-conducting drum withfluid-conducting passages in its wall, perforate means positioned at oneend of the drum for supporting and rotating the drum about its axis,said means having passages which communicate with the opposite ends ofthe uid-conducting passages in the wall of the drum and having arelatively short dimension axially of the drum, and Scrapers which bearon the inner and outer walls of the drum to insure a relative rotationalvelocity between the drum and any liquid in which it is rotated andprevent the formation of surface lms which adhere to the Wall of thedrum and decrease the rate of heat transfer.

ADAM ZISKA.

